online web based tool -not the desktop

Care to explain? If you have a script designed to work as a desktop tool for what you need, then chances are that a minimal set of modifications can turn it into say a CGI script or similar.

More precisely what you're asking for is rather vague and the more probable answer you're likely to get is one along the lines of those you've already received thus far: either pointing to some snippet or to a suitable module. Then it's up to you to put everything together in a complete working program (web based, if you like!) suited for your needs.